Polyvinyl acetal resin sheet containing benzyl maleate



.25 property which, in

. 3 renders such sheets, which I shall call Patented Sept. 3, 1940 roLYvmL mmmo Donald R. Swan, Rochester, N.

Eastman Kodak Company, Roc corporation of New Jersey Application September 23, 1939, Serial No. 296,304

No Drawing.

4 Claims;

This invention relates to polyvinyl acetal resin sheets, and more particularlyto sheets suitable for the manufacture of safety glass.

One object of my invention is to produce compositions of matter which can be made into permanently transparent sheet. suitable for use in laminated, shatter-proof glass. Another object is to produce compositions which can be rolled,

extruded, molded, or otherwise worked into relatively thick sheets and massive plastics. Other objects will hereinafter appear.

I have discovered that benzyl maleate is a usefulplasticizer'for polyvinyl acetal resins, such,

for instance, as polyvinyl acetaldehyde acetal resins, polyvinyl formaldehyde acetal resins, and

polyvinyl butyraldehyde acetal resins. Furthermore, I have discovered that when 40 or more parts of benzyl maleate is used with 100 parts of a polyvinyl acetal resin, an unusual and remark able effect is obtained which I may call elasticizing. That is to say, a sheet of polyvinyl acetal resin containing about 40 or more parts of benzyl maleate per 100 parts of resin is not only permanently transparent, but it possesses the the rubber industry, is known as "nerve: namely, to a considerable extent when tension is exerted upon it, and returning to its original dimensions when the tension is released. This property y sheets, particularly useful shatter-proof glass. When the resin used is a polyvinyl formaldehyde or acetaldehyde acetal resin, it will usually be found necessary to use 35 60 or more parts of benzyl maleate per 100 parts of resin in order to obtain this rubbery property.

Sheets for use in laminated glass may be made by dissolving the polyvinyl acetal resin and the 40 benzyl maleate in a suitable volatile solvent or solvent mixture, such, for instance, as acetone, methanol, acetone-methanol mixtures, ethylene chloride-methanol mixtures, etc., about 300 to 500 or more parts of the solvent or solvent mix- 45 ture being used per 100 'parts of the resin. The solution is then cast as a sheet, the volatile solvent evaporated, and the sheet stripped from the casting surface.

Sheets for use in laminated glass may also be so made without the use of volatile solvent by extrusion, for example, in the manner set forth in application Serial No. 147,934 of John S. Kimble and Enest C. Blackard, filed June 12, 1937. For example, 40 or more parts of benzyl maleate .55 and 100 parts of a.

the property of stretching.

in the manufacture of polyvinyl acetal resin may ACETAL RESIN SHEET CON- BENZYL MALEATE Y., assignor to hester, N. Y., a

' be mixed in a suitablaiacketed mixer at a low temperature, for example 10 0., and the mixture" may then be worked on hot rolls, in the manner described in U. S. Patent 2,048,686 of F. R. Conklin, until complete homogenization has taken place. The mass thus produced may then be extruded through an annular die, and the tube so formed slit to form a sheet.

The polyvinyl acetal resins can be prepared by reacting polyvinyl lcohol with an aldehyde in the presence of an acetal condensation catalyst, e. g., a mineral acid. These resins can also be prepared by simultaneously de-esterifying a polyvinyl aliphatic ester and reacting the deesterification product with an aldehyde in the presence of a de-esterifying catalyst and acetal condensation catalyst. Mineral acids are catalysts for both de-esterification and acetal formatiOn'. Examples of the preparation of polyvinyl formaldehyde acetal resins may be found in U. 8. Patent 1,955,068, Examples 1, 4 and 5; in U. 8. Patent 2,036,092, Examples 1, 2, 3, '7 and 8; in British Patent 454,691, Examples '1, 2, 3, 4, 5, 6 and '7; in British Patent 404,279, Example 3; and in British Patent 436,072, Examples 1, 2, 3, 4, 5, 6 and 7. Further examples of the preparation of polyvinyl formaldehydeacetal resins are as follows:

lbs. of polyvinyl acetate, the viscosity of whose molar solution (86.08 g. per liter) in benzene was as centipoises, was dissolved in '15 lbs. of 70% acetic acid. To this solution were added 56 grams of hyroxylamine hydrochloride, for stabilizing the resin, 5.25 lbs. of trioxymethylene, and 6.25 lbs. of HCl. The reaction mixture was allowed to stand for 5 days at 40 C., after which it was diluted with acetic acid. The resin was precipitated'by pouring into cold water, washed, and dried. Analysis showed the resin to have an acetate group content equivalent to 10.6% by weight of polyvinyl acetate and a hydroxyl group content equivalent to 7.1% by weight of polyvinyl alcohol. 1

70 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was centipoises, was dissolved in a mixture of 336 lbs. of glacial acetic acid and 224 lbs. of water. After solution was effected, there were added a. solution of 3l8grams of sodium nitrite in 500 cc. of water, for stabilizing the resin, 15.2 lbs. of trioxyrriethylene and 17.5. lbs. of 35% H01. The reaction mixture was allowed to stand for 5 days at 49 C., whereupon 5 lbs. additional 35% HCl was added and the reaction continued for 6 days 55 acetic acid and'ethyl alcohol, and the resin was Patent 2,044,! 30,

"1,2and3.

pies 1, 2, 3, 4 and 7;

precipitated by pouring into cold wa washed, and dried. Analysis showed the resin to have an acetate group content equivalent to 10.7% by weight of polyvinyl acetate and a hydroxyl group content equivalent to 11.2% by weight of ,polyvinyl alcohol. Examples 01' the preparation of polyvinyl acetaldehyde acetal resins may be found in U. 8. Example 1; U. 8. Patent 1,955,068, Example 2; U. 8. Patent 2,036,092, Examples 4, 5 and 6; British Patent 466,598, ham- British Patent 404,279, Examples 1,2, 4, 5, 6, 7 and-8; U. 8. Patent 1,990,399; and French Patent 808,578, Examples Additional examples of the preparation oi polyvinyl acetaldehyde acetal resins are as follows:

100 lbs. of polyvinyl acetate,

the viscosity of whose molar solutionin benzene was 45 centipoises, was dissolved in 300 lbs. of 95% ethyl alcohol. To this solution was added 30 lbs. 01' paraldehyde and 25 lbs. 01' 35% HCl. The reaction mixture was allowed to stand for 4 days at 40 C., after which it was-diluted with ethyl alcohol. and the resin precipitated by pouring into cold water, washed and dried. Analysis. showed the resin to have an acetate group content equivalent to 2.1% by weight of polyvinyl acetate and a hydroxyl group content equiva- "lent to 12.9% by weight of polyvinyl alcohol.

25 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was 45 centipoises, wasdissolved in 75 lbs. of 95% ethyl'alcohol. To this solution was added 8 lbs.- of

= paraldehyde and a solution of 3 lbs. 12 oz. of k sulfuric acid in 3 lbs.

I 12 oz. of 95% ethyl alcohol. The reaction mixture was allowed to stand for 7 days at 40 C., after which it was diluted with ethyl alcohol, and the resin precipitated by pouring into cold water, washed, and dried. Analysis, showed the resin to have an acetate group content equivalent to 1.7 by weight of polyvinyl acetate and a hydroxyl group content equivalent to 13.8% by weight of polyvinyl alcohol.

Examples of the preparation of polyvinyl butyraldehyde acetal resins may be found in U.

S. Patent 2,044,730, Examples 2, 5 and 6; British Patent 466,598, Example 5; French Patent 813,303, Example 1; French Patent 813,514, Examples 1, 2,. 3 and 4; and British Patent 459,- 878, Examples 1, 2, 5, 6, '7, 8, 9 and 10. An additional example of the preparation of a polyvinyl butyraldehyde acetal resin is as follows:

23.6 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was 45 centipoises, was dissolved in 56.5 lbs. of 95% ethyl alcohol. vTo this solution was added 7.9 lbs.

of butyraldehyde and 5.9 lbs. of 35% HCl. The

l. A transparent, rubbery sheet comprising 100 parts of a polyvinyl acetal resin and at least 40 parts, approximately, of benzyl inaleate as an elasticizer therefor.

2. A transparent, rubbery sheet comprising 100 parts of a polyvinyl acetaldehyde acetal resin and at least 60 parts, approximately, of benzyl maleate as an elasticizer therefor.

3. A transparent, rubbery sheet comprising 100 parts of a polyvinyl formaldehyde acetal resin and at least 60 parts; approximately, of benzyl maleate as an elasticizer therefor.

4. A transparent, rubbery sheet comprising 100 parts cl 2, polyvinyl butyraldehyde acetal 'resin and at least40 parts, approximately, of benzyl maleate as an elasticizer therefor.

DGNALD R. SWAN. 

